2-Player Nash and Nonsymmetric Bargaining Games: Algorithms and Structural Properties

The solution to a Nash or a nonsymmetric bargaining game is obtained by maximizing a concave function over a convex set, i.e., it is the solution to a convex program. We show that each 2-player game whose convex program has linear constraints, admits a rational solution and such a solution can be found in polynomial time using only an LP solver. If in addition, the game is succinct, i.e., the coefficients in its convex program are ``small'', then its solution can be found in strongly polynomial time. We also give a non-succinct linear game whose solution can be found in strongly polynomial time

The determination and evaluation of Nitinol constitutive models for finite element analysis

Superelastic Ni-Ti (Nitinol) is a member of the shape memory alloy (SMA) family of metals. The physical properties of Nitinol are highly dependant on a number of factors, including manufacturing method, subsequent processing, operating temperature, and strain rate. These factors complicate the prescription of material constitutive models, leading to complexities in the computational analysis of Nitinol components. The current work explores the limitations in the Nitinol material model available in existing commercial finite element (FE) software using a series of specially design experimental tests and representative FE models

Preferences for Prenatal Tests for Cystic Fibrosis: A Discrete Choice Experiment to Compare the Views of Adult Patients, Carriers of Cystic Fibrosis and Health Professionals

As new technologies enable the development of non-invasive prenatal diagnosis (NIPD) for cystic fibrosis (CF), research examining stakeholder views is essential for the preparation of implementation strategies. Here, we compare the views of potential service users with those of health professionals who provide counselling for prenatal tests. A questionnaire incorporating a discrete choice experiment examined preferences for key attributes of NIPD and explored views on NIPD for CF. Adult patients (n = 92) and carriers of CF (n = 50) were recruited from one children’s and one adult NHS specialist CF centre. Health professionals (n = 70) were recruited via an e-mail invitation to relevant professional bodies. The key attribute affecting service user testing preferences was no miscarriage risk, while for health professionals, accuracy and early testing were important. The uptake of NIPD by service users was predicted to be high and includes couples that would currently decline invasive testing. Many service users (47%) and health professionals (55.2%) thought the availability of NIPD for CF would increase the pressure to undergo prenatal testing. Most service users (68.5%) thought NIPD for CF should be offered to all pregnant women, whereas more health professionals (68.2%) thought NIPD should be reserved for known carrier couples. The implications for clinical practice are discussed

Analysis of dynamic stall using unsteady boundary-layer theory

The unsteady turbulent boundary layer and potential flow about a pitching airfoil are analyzed using numerical methods to determine the effect of pitch rate on the delay in forward movement of the rear flow reversal point. An explicit finite difference scheme is used to integrate the unsteady boundary layer equations, which are coupled at each instant of time to a fully unsteady and nonlinear potential flow analysis. A substantial delay in forward movement of the reversal point is demonstrated with increasing pitch rate, and it is shown that the delay results partly from the alleviation of the gradients in the potential flow, and partly from the effects of unsteadiness in the boundary layer itself. The predicted delay in flow-reversal onset, and its variation with pitch rate, are shown to be in reasonable agreement with experimental data relating to the delay in dynamic stall. From the comparisons it can be concluded (a) that the effects of time-dependence are sufficient to explain the failure of the boundary layer to separate during the dynamic overshoot, and (b) that there may be some link between forward movement of the reversal point and dynamic stall

Distributed lag models for hydrological data

The distributed lag model (DLM), used most prominently in air pollution studies, finds application wherever the effect of a covariate is delayed and distributed through time. We explore the use of modified formulations of DLMs to provide flexible varying-coeficient models with smoothness constraints, applicable in any setting in which lagged covariates are regressed on a time-dependent response. The models are applied to simulated flow and rainfall data and to flow data from a Scottish mountain river, with particular emphasis on approximating the relationship between environmental covariates and flow regimes in order to detect the influence of unobserved processes. It was found that under certain rainfall conditions some of the variability in the influence of rainfall on flow arises through a complex interaction between antecedent ground wetness and the time-delay in rainfall. The models are able to identify subtle changes in rainfall response, particularly in the location of peak influence in the lag structure and offer a computationally attractive approach for fitting DLMs

Global atmospheric circulation statistics: Four year averages

Four year averages of the monthly mean global structure of the general circulation of the atmosphere are presented in the form of latitude-altitude, time-altitude, and time-latitude cross sections. The numerical values are given in tables. Basic parameters utilized include daily global maps of temperature and geopotential height for 18 pressure levels between 1000 and 0.4 mb for the period December 1, 1978 through November 30, 1982 supplied by NOAA/NMC. Geopotential heights and geostrophic winds are constructed using hydrostatic and geostrophic formulae. Meridional and vertical velocities are calculated using thermodynamic and continuity equations. Fields presented in this report are zonally averaged temperature, zonal, meridional, and vertical winds, and amplitude of the planetary waves in geopotential height with zonal wave numbers 1-3. The northward fluxes of sensible heat and eastward momentum by the standing and transient eddies along with their wavenumber decomposition and Eliassen-Palm flux propagation vectors and divergences by the standing and transient eddies along with their wavenumber decomposition are also given. Large interhemispheric differences and year-to-year variations are found to originate in the changes in the planetary wave activity

Why do planetary wave number one and the ozone transport vary annually in the Northern Hemisphere and semiannually in the Southern Hemisphere

Evidence is cited from these studies and those of others showing the different nature of the yearly variations of the middle atmospheres of the Northern and Southern Hemispheres. The Northern Hemisphere middle atmosphere is shown to be characterized by annual variations in planetary wave number one amplitude and the accompanying ozone transports. The Southern Hemisphere middle atmosphere is shown to be characterized by semiannual variations in the amplitude of planetary wave number one and the accompanying ozone transports. The amplitude of wave number two in both hemispheres appears to vary annually. Examination is made of the nature of the planetary wave forcing in both hemispheres as well as the planetary wave propagation characteristics in both hemispheres in an attempt to better understand this

Aventurescence

Aventurescence explores ideas of comfort and identity through glass and the body. I am interested in the material qualities and limitations of glass, including luminosity, flexibility, and fragility; and the ways in which these can be expressed and communicated through the body. To expand the material’s flexibility I used a combination of multiple glass bodies and silicones to create glass textiles and objects with flexible surfaces. I also used traditional fusing methods and alternative glasses (reflective glass beads) to create sheets and screens. These objects and textiles parallel skin, and communicate with the body through object, performance, and the consequent documentation of performance. The culmination of my research was a cohesive body of work, utilizing the body, silicones, and glass, to create objects, performance, and installation

Poverty and some of its effects upon school children

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Results of the Accreditation Process to Guide Postsecondary Certificate-Granting Institution Improvement

Research gaps exist in knowledge about postsecondary certificate-granting institutions, as well as results of accreditation processes. This qualitative study focuses on national accreditation results that can: 1) define strengths and improvement areas in these institutions; 2) determine why action is taken or not taken on accreditation recommendations; and 3) identify results, strengths, and challenges of accreditation. This research base can guide improvements in these institutions and the North Central Association – Commission on Accreditation and School Improvement (NCA CASI) process. The population was 125 accredited schools in ten states, representing 96% of all NCA CASI accredited public, postsecondary institutions. Methods included: document analysis, interviews, and peer review validation. All commendations and recommendations in the 125 school NCA CASI accreditation reports were coded. Interview participants were selected using a maximum variance sampling with completion and licensure/certification passage averages as the variance component. Interviews were conducted with selected 15 NCA CASI school coordinators, one State Department Coordinator and one AdvancED/NCA CASI representative. Seven school personnel from five states participated in a peer-review validation process. Results indicate: 1) the accreditation report documentation shows the highest percentage of schools receive commendations related to: business, industry and community involvement; pupil personnel services; positive school culture and relationships; safety and space considerations, and data collection processes. Highest percentage of schools recommendations focused on: data analysis and decisions; lack of space; student support service strategies; business, industry, and community support strategies; and increased documentation. 2) Interviews identified themes of action taken on accreditation report recommendations: documentation, compliance, performance measures, and process improvements. Actions not taken related to: resource costs or philosophical differences. 3) Accreditation process strengths are: financial aid access; credibility; continuous improvement framework; critical analysis of self study using internal teams; and gaining external peer-review team perspectives. Accreditation challenges or areas in need of improvement are: accountability duplication; resource constraints; subjectivity/ philosophical differences; and suggestions for process improvements. These NCA CASI accredited institutions show an average of 84.5% completion, 87.9% placement, and 89.7% licensure/certification performance rates